Oregon-Washington Dead Zones: Global Warming and Anoxic Oceans

This is what’s happening to the coasts off of Oregon and Washington (as well as oceans around the world). The oceans are becoming more and more acidic, in a process called acidification. And that bodes poorly for creatures who are sensitive to rising acid levels (most).

There are an increasing number of Dead Zones in the waters of the world. A Dead Zone is a patch of ocean that is so devoid of oxygen that nothing (or nearly nothing) can live in it. As a point of reference, the bottom of the appropriatly named Black Sea is black because below 150 meters the water is anoxic (without oxygen), and there is no life (except certain bacteria) — just a bleak, black nothingness.

At more than one point in the earths history, the oceans — all of the oceans — were completely anoxic. No life was found in them save for some particularly noxious bacterium that released large amounts of poisonous (to humans and other animals) gas. Nearly all the major extictions of the past (save for the KT asteroid extinction) happened in conjunction with anoxic oceans.

These dead spots are growing. The mouth of the Mississippi is now the 3rd largest dead zone in the world, every year growing to 20, 000 square kilometers. It grows in summer, shrinks in winter.

Peering into the murky depths, Jane Lubchenco searched for sea life, but all she saw were signs of death.

Video images scanned from the seafloor revealed a boneyard of crab skeletons, dead fish and other marine life smothered under a white mat of bacteria. At times, the camera’s unblinking eye revealed nothing at all — a barren undersea desert in waters renowned for their bounty of Dungeness crabs and fat rockfish.

“We couldn’t believe our eyes,” Lubchenco said, recalling her initial impression of the carnage brought about by oxygen-starved waters. “It was so overwhelming and depressing. It appeared that everything that couldn’t swim or scuttle away had died.”

Upon further study, Lubchenco and other marine ecologists at Oregon State University concluded that that the undersea plague appears to be a symptom of global warming. In a study released today in the journal Science, the researchers note how these low-oxygen waters have expanded north into Washington and crept south as far as the California state line. And, they appear to be as regular as the tides, a lethal cycle that has repeated itself every summer and fall since 2002.

“We seem to have crossed a tipping point,” Lubchenco said. “Low-oxygen zones off the Northwest coast appear to be the new normal.”